TCP (Tape Carrier Package) has been used as a measure for electrically connecting between a LCD display panel, for example, and an external device, for example, through a driver IC chip.
FIG. 5 illustrates the overall structure of the existing TCP.
As shown in FIG. 5, this TCP 101 has a device hole 112, which is opened in an area slightly larger than the driver IC chip 111, at the central part of the base film 102, which is made of a resin, such as polymide, for example, and it has multiple leads 104, which are connected to an external device, and multiple leads 105, which are connected to an LCD display panel. The driver IC chip 111, with the inner lead of each of the leads 4 and 5 connected to an electrode pad (not shown in the figure) that is formed over the said IC chip 111, is installed at the device hole 112. Furthermore, the driver IC chip 111 as well as the device hole 112 are sealed with a resin, which forms an overcoat area 103.
Multiple outer leads 104A at the input side of the leads 104 and outer leads 105A at the output side of the leads 105 are formed adjacent to each other.
With advancements in the attainment of fine pitch and the many pins for the external leads 105A at the output side that accompany high resolution in liquid crystal panels in recent years, this type of TCP is often connected to connecting terminals of a LCD display panel by an anisotropic conductive adhesive film (ACF) that contains conductive particles in a binding resin.
FIG. 6 illustrates a process in which a TCP 101 is mounted onto a LCD display panel by using an anisotropic conductive adhesive film.
As shown in FIG. 6, an anisotropic conductive adhesive film, which is not shown in the figure, is held between a lower glass panel 106 and the connection region 102A at the output side of the base film 102 of the TCP 101, and a thermocompression bonding heating tool 108 is pressed from above the upper glass panel 107. As a result, the base film 102 of the TCP 101 is bonded to the lower glass panel 106 by the binding resin in the anisotropic conductive adhesive film, and the outer lead 105A at the output side of the TCP 101 is also connected to the electrode pattern of the lower glass panel 106 by the conductive particles within the anisotropic conductive adhesive film at the same time.
On the other hand, the pitch of the outer lead 104A at the output side of the TCP 101 is larger than that of the outer lead 105A at the output side, therefore, it is generally connected to a printed substrate, for example, by soldering.
However, demands for attaining fine pitches and many pins particularly at the outer lead 105A of the output side of the TCP 101 have been increasing in recent years. Reasons for this include, for example: an attempt to reduce cost by decreasing the number of parts in the connection of the LCD display panel, and a reduction in cost for a driver per channel. As a result, one that has a pitch among the outer leads 105A at the output side at 70 .mu.m and 240 channels, and one that has the said pitch at 110 .mu.m and 309 channels, for example, have been put into practical use in recent years.
However, the base film 102 is thermally expanded during the thermocompression bonding described above in the existing TCP 101, the position of the outer lead 105 at the output side is shifted, and positioning between the outer lead 105 and the electrode pattern 109 over the glass panel 106 becomes difficult as with difficulty in obtaining more pins.
For example, in the TCP 101 shown in FIG. 5, the base film 102 during a thermocompression bonding expands in directions that spread out towards both sides (directions of the arrows), the outer leads 105A at the output side at both edge areas in particular are significantly shifted, and as a result, positioning with the electrode pattern 109 over the glass panel 106 becomes difficult. Additionally, there is the problem of positioning becoming more difficult when an attempt is made to obtain many pins by narrowing the pitch among the outer leads 105A.
The aim of this invention, which was made to solving said problem in the existing technology, is to offer a tape carrier package which has easy positioning during the connection to an external device so that many pins and a fine pitch can be simultaneously attained.